Yeah I was going with my quick and dirty numbers from earlier. Way I see it what’s probably happening is that doubling time for Britain as a whole has been ~2 weeks both about a month ago and recently (eyeballing graph from worldometer), and you are probably talking about a new doubling time of ~1 week for this variant under identical conditions.
Redoing math for a two week starting doubling time and the stated change in doubling time you get a R value going from ~1.25 to just under or circa 1.5, so basically similar order.
News sources do not use precise language, and precise language matters here.
“We find that Rt increases by 0.57 [95%CI: 0.25-1.25] when we use a fixed effect model for each area. Using a random effect model for each area gives an estimated additive effect of 0.74 [95%CI: 0.44- 1.29].
an area with an Rt of 0.8 without the new variant would have an Rt of
1.32 [95%CI:1.19-1.50] if only the VOC was present.”
But for R, if it’s 0.6 not 0.8 and the ratio is fixed then another march style lockdown in the UK would give R = 0.6 *(1.32/0.8)= 0.99
I’ve been trying to understand this discussion (and I agree that this is one of the central questions for the model of how things will progress from here, in particular if March-style lockdowns will be sufficient or not to halt the spread of this strain). But now I’m mainly confused—isn’t such a dramatic increase in Rt incompatible with the slower increase in the graph, as pointed out by CellBioGuy?
Edit: I’ve read yesterday’s PHE investigation report, and they do explicitly confirm it is an increase of over +0.5 to the Rt under the conditions in England in weeks 44-49 of this year. So this seems like the bad possible interpretation, where it really does spread significantly more.
Yeah I was going with my quick and dirty numbers from earlier. Way I see it what’s probably happening is that doubling time for Britain as a whole has been ~2 weeks both about a month ago and recently (eyeballing graph from worldometer), and you are probably talking about a new doubling time of ~1 week for this variant under identical conditions.
Redoing math for a two week starting doubling time and the stated change in doubling time you get a R value going from ~1.25 to just under or circa 1.5, so basically similar order.
News sources do not use precise language, and precise language matters here.
Update: this from public health England explicitly says Rt increases by 0.57, https://twitter.com/DevanSinha/status/1341132723105230848?s=20
“We find that Rt increases by 0.57 [95%CI: 0.25-1.25] when we use a fixed effect model for each area. Using a random effect model for each area gives an estimated additive effect of 0.74 [95%CI: 0.44- 1.29].
an area with an Rt of 0.8 without the new variant would have an Rt of 1.32 [95%CI:1.19-1.50] if only the VOC was present.”
But for R, if it’s 0.6 not 0.8 and the ratio is fixed then another march style lockdown in the UK would give R = 0.6 *(1.32/0.8)= 0.99
I’ve been trying to understand this discussion (and I agree that this is one of the central questions for the model of how things will progress from here, in particular if March-style lockdowns will be sufficient or not to halt the spread of this strain). But now I’m mainly confused—isn’t such a dramatic increase in Rt incompatible with the slower increase in the graph, as pointed out by CellBioGuy?
Edit: I’ve read yesterday’s PHE investigation report, and they do explicitly confirm it is an increase of over +0.5 to the Rt under the conditions in England in weeks 44-49 of this year. So this seems like the bad possible interpretation, where it really does spread significantly more.